It is generally desirable to modify surfaces such that they have little tendency if any to become soiled. Such surfaces look esthetic for a prolonged period, remain free of bacterial or fungal growth and, if or when they are cleaned, are particularly easy to clean.
State of the art methods for producing surfaces possessing a low tendency to become soiled frequently utilize the Lotus Effect®, for example WO 96/04123 and EP-B 1 171 529. To endow a surface with a Lotus Effect, one may for example provide surfaces in the manner of the lotus plant with a microrough surface, for example with elevations and depressions in such dimensions that the elevations are from 5 to 200 μm spaced apart and from 5 to 100 μm high and the elevations at least consist of, for example, hydrophobic polymers and are not detachable by water or water with detergents. Thus endowed surfaces are observed to have a large contact angle with water, for example 157°, see for Example 9 of U.S. Pat. No. 3,354,022. Soil particles have low adhesion to thus endowed surfaces and are easily removed by rinsing off with water.
However, textile surfaces endowed with Lotus Effect are disadvantageous in that they are not pervious to perspiration. Yet perspiration perviousness is desirable in many cases for garments in particular.
It is also desirable that diapers retain urine and do not occasion urine drop formation. This holds for example for diapers produced by use of polypropylene and of superabsorbents.
Another method for endowing surfaces to be soil repellent consists in rendering them very hydrophilic. Water then forms a film and easily detaches soil particles, see for example WO 03/66710.
WO 01/83662 discloses that certain particles from 5 to 500 nm in size can be used to treat textiles in order that they may be soil repellent for a certain period, generally up to 4 washing or cleaning cycles (last paragraph on page 2). Such short finish lives are undesirable in some applications, however.
DE-A 101 16 200 discloses that surfaces can be coated with very finely divided inorganic particles, surface modifiers and if appropriate a surfactant and that the surfaces subsequently possess antimisting properties. Such coatings, however, do not survive a wash cycle without being impaired.